1. Field of Invention
This invention relates to the field of fluid flow amplifiers and, in particular, to fluid flow amplifiers in combination with machines the operation of which requires supply of a gas flow. An example of such a machine is an air compressor, e.g., in the form of a turbocharger for enhancing supply of air to a combustion engine. More specifically, the invention relates to a fluid flow amplifier for moving a cold, powerful atmospheric centripetal airflow across a turbine of the turbocharger. The fluid flow amplifier allows for the entire rotating assembly of the turbocharger to be made of super-light-weight materials that are not concerned with heat issues of hot exhaust gases from a combustion engine. The reduction of weight gives the turbocharger super low inertia characteristics with rapid transit response ability and ideal power consumption for operation.
2. Prior Art
Such devices as a centrifugal blower or a turbocharger are known as dynamic air compressors. An impeller being a working element of the compressor needs to rotate at a high speed such that ambient air is drawn into the center of the impeller and then is thrown off the periphery of the impeller at a high speed. A diffuser known as a convergent-to-divergent nozzle slows the high velocity air down and exchanges it for an increase of pressure. A turbocharger is a device driven by exhaust gases typically flowing from a combustion engine. Normally, a centrifugal blower has a larger impeller than a turbocharger and is driven off the crankshaft via a pulley and belt or through a gearing system in order to obtain a high impeller velocity. Centrifugal blowers can also be powered by other means such as electric motors via a belt or gearing transmission.
Compressed air produced from the turbocharger or centrifugal blower can be used for pneumatic applications, e.g., for increasing power output due to supply of an induced air flow.
In a simplified schematic form, the existing arrangements of a turbocharger or another machine, such as a centrifugal blower that is used for enhancing operation of an internal combustion engine or for creating a flow of compressed air for other possible purposes, can be illustrated by arrangements shown in FIGS. 1 to 3 below.
FIG. 1 is a simple schematic view illustrating a known arrangement consisting of an internal combustion engine and a turbocharger powered by exhaust gas from the exhaust system of the engine. The arrangement shown in FIG. 1 consists of an internal combustion engine 10 having an air intake 12 and an exhaust outlet 18. The exhaust outlet 18 is connected to an input of a gas turbine 22 that has an output shaft 28 used for driving a centrifugal compressor 24. The outlet of the centrifugal compressor 24 is connected to the air intake 12.
As the internal combustion engine 10 operates, hot exhaust gas enters the gas turbine 22 and expands. A flow of exhaust gas from the engine 10 to the turbine 22 is shown in FIG. 1 by arrow 20. An expanded gas that leaves the turbine is shown by arrow 26. The turbine 22 transmits the power provided by the hot exhaust gas 20 to the shaft 28, which transfers the power to the centrifugal compressor 24 which is connected to the shaft 28. The centrifugal compressor 24 begins to spin at high velocity, and a flow of low pressure air shown by arrow 16 is drawn into the centrifugal compressor 24 where it is compressed to a higher pressure. A flow of compressed air shown by arrow 14 is supplied from the centrifugal compressor 24 to the air intake 12 of the internal combustion engine 10. The internal combustion engine 10 sees more air such that more fuel is added, thus producing more output power.
FIG. 2 is a simple schematic view illustrating a known arrangement consisting of an internal combustion engine and a centrifugal blower powered by the crankshaft of the engine. The arrangement consists of an internal combustion engine 10a that has an air intake 12a, an exhaust outlet 18a, a crankshaft 30, and a power transfer mechanism 32, such as a gearing system driven from the engine 10a via the crankshaft 30 and having its output shaft 28a connected to a centrifugal compressor 24a. The outlet of the centrifugal compressor 24a is connected to the air intake 12a of the engine. In operation, the engine 10a drives the power transfer mechanism 32 via the crankshaft 30, and the transfer mechanism 32, in turn, transmits the power to the centrifugal compressor 24a via the shaft 28a. The centrifugal compressor 24a begins to spin at a velocity dependent on the step up ratio of the transfer mechanism 32. The step up ratio can be, e.g., 5:1, meaning the centrifugal compressor 24a will spin 5 times faster than the speed of the crankshaft 30. The speed of the centrifugal compressor 24a is, therefore, depends on crankshaft 30 rpm. Low-pressure air, e.g., atmospheric air shown by arrow 16a, is drawn into the centrifugal compressor 24a and is compressed to a higher pressure flow that is shown by arrow 14a. The high-pressure air flow 14a enters intake 12a of the internal combustion engine 10a and force-inducts the air of the internal combustion engine 10a. The internal combustion engine 10a sees more air such that more fuel is added, thus producing more output power.
Shown in FIG. 3 is a simple schematic view that illustrates how a centrifugal blower can be powered by an electric motor. An electric power source 54 supplies electric power to an electric motor 56. An output shaft 50 of the electric motor 56 is the electric motor 56 is connected to a power transfer mechanism 32b, which can typically be a gearing system, such as a transmission or a pulley system. An output shaft 28b is connected to centrifugal compressor 24b and drives the latter. The centrifugal compressor 24b begins to spin at a velocity that depends on the step up ratio of the power transfer mechanism 32b. The step up ratio between the engine and the centrifugal compressor can be, e.g., 7:1, meaning the centrifugal impeller will spin 7 times faster than the speed of the output shaft 50. The speed of the centrifugal compressor 24b, therefore, depends on the rpm of the electric motor 56. A low-pressure air flow shown by arrow 16b is drawn into the centrifugal compressor 24b and is compressed to a higher pressure. A flow of high-pressure air which is released from the compressor 24b and shown by arrow 14b can be used for pneumatic applications, e.g., for driving a pneumatic tool (not shown). The electrical powered centrifugal blower typically is rarely used as a force induction component for an internal combustion engine due to high electrical power requirements. Therefore, such electric powered centrifugal blowers are used for expensive pneumatic operations.
The above arrangements are embodied into structural designs in the patents mentioned below for illustration purposes.
U.S. Pat. No. 7,028,677 issued in 2006 to Martin presents an external drive supercharger is described. The external drive supercharger includes an impeller, a multibelt pulley adapted to a drive source, an impeller pulley drivingly coupled to the impeller, and an external drive belt having at least one rib coupled to the multibelt pulley to drive the impeller pulley. Further, the external drive assembly includes an adjustable idler engagingly connected to the external drive belt wherein the impeller pulley and the multibelt pulley engage with the at least one rib of the external drive belt.
the radial guide cascade ring are no longer in contact with the wall, so that a direct, unobstructed flow path to an outflow duct is provided in the exhaust-gas turbine.
U.S. Pat. No. 7,028,677 issued in 2006 to Martin discloses an external drive supercharger. The external drive supercharger includes an impeller, a multi-belt pulley adapted to a drive source, an impeller pulley drivingly coupled to the impeller, and an external drive belt having at least one rib coupled to the multi-belt pulley to drive the impeller pulley. Further, the external drive assembly includes an adjustable idler engagingly connected to the external drive belt, wherein the impeller pulley and the multi-belt pulley engage with at least one rib of the external drive belt.
U.S. Pat. No. 5,638,796 issued in 1997 to Adams, III, et al presents an electrically driven supercharger. The electrically driven supercharger described in the above patent comprises a centrifugal blower for compressing air. The blower is mounted on one end of a shaft. A first bearing is provided for supporting the blower on said one end of said shaft in a cantilever fashion. The rotor of an electric motor is mounted on the opposite end of said shaft. A second bearing is provided for supporting the rotor on said opposite end of the shaft in a cantilever fashion. A lubricating fluid container is located between the first and the second bearings for containing a quantity of lubricating fluid. A slinger is also mounted on the shaft, which passes through the lubricating fluid container, for slinging the lubricating fluid against the first and second bearings. The motor, which is a brushless d-c motor, is designed to provide in response to a 50 to 100 volt applied potential, approximately 10 horse power at approximately 60,000 rpm's.
In the field of turbochargers the rotating assembly, which comprises a compressor and a turbine, are typically heavy. This heaviness of the rotating assembly leads inventors to find out ways to help combat turbo lag, which is the time needed for turbocharger to spin up to speed vs. the time the gas pedal is depressed. Turbo lag is caused by the heavy rotating assembly of the turbocharger.
Arrangements of components that enhances pressure differential between the inlet and outlet of a turbocharger system that utilizes a flow of gas to spin up quicker are known in the art.
For example, a device described in U.S. Pat. No. 5,064,423 issued in 1991 to Lorenz et al., supplies compressed air from a pressurized tank to an intake of the internal combustion engine to provide a higher flow of hot expanding gases to enhance the pressure differential, which helps spool the turbocharger quicker.
U.S. Pat. No. 5,819,538 issued in 1998 to Lawson Jr. utilizes a method to enhance a turbocharger by re-circulating turbocharged air during injection of compressed air to the intake of an internal combustion engine. This helps to provide a higher flow of hot expanding gases to enhance the pressure differential in the turbine housing.
U.S. Pat. No. 6,826,910 issued to M. Easton in 2004 discloses an internal combustion engine that includes an air amplifiers to increase airflow. Air amplification with a high-pressure supply provides a practical way to for creating a large airflow needed to generate higher power for rear wheels. When synchronized to the valve openings, the efficiency is enhanced while adding to the system complexity. These additions also apply to an engine with a supercharger of turbocharger. When used in the exhaust path, the air amplifiers can also help scavenge exhaust gases from the cylinder for added power.
A most all devices and methods mentioned above have a common objective, which is to use compressed air from a source such as a pump or tank and supply the compressed air to the intake manifold of the combustion engine directly or through some auxiliary boosting device, one above being an air amplifier.
The use of compressed air on even moderately sized engines requires a large flow of compressed air. There are physical limitations on the flow rate of compressed air into ambient pressure. Physics dictates the speed of sound is the limit at which air will flow through a nozzle from an external tank. Therefore for a given valve diameter or nozzle there is a limit to the flow rate. It is possible to have larger diameter nozzles but controlling the flow with large valves becomes much less practical. An air flow amplifier as mentioned in the above patent by M. Easton, however, has great potential. It is a device that entrains a large volume of a secondary air flow from a surrounding atmosphere by means of a high-speed primary flow of pressurized air to the air amplifier from the external source. Air amplifiers can produce large flow rates that are powerful.
A common disadvantage, however, of all known devices of the aforementioned type is that no effort is made to decrease the heaviness of the rotating assembly of the turbocharger, but rather inventors cope the heaviness by using compressed air boosting methods mentioned above. Considering that the hot expanding exhaust gas from an internal combustion engine is what typically drives a turbocharger and that heat-resistant materials are typically heavy, the compressed air boosting methods to combat the heaviness of the turbocharger are, therefore, dependent on the turbocharger, that is dependent on the hot expanding exhaust gases from an internal combustion engine.
A centrifugal blower, however, can have a light-weight assembly because there is no turbine needed and because it is driven from the crankshaft via a pulley or gearing system. However, such a method requires more power than an exhaust-driven turbocharger because of the surface-to-surface contact between the parts of the gearing or pulley system. Another disadvantage of using gears or pulleys is that the power, required to increase impeller speed goes up dramatically because of the friction associated with the gearing or pulley system, increases dramatically as speed is increased. Such a centrifugal blower cannot be readily turned by hand, which labels it a high power consumption machine needing more power than necessary, unlike a turbocharger which can be readily spun by turning either the compressor or turbine wheel, especially if the turbocharger is supported by ceramic bearings. This makes turbochargers much more efficient than centrifugal blowers.